1. Field of the Invention
The present invention relates to a manufacturing method of a flat-panel display unit used for a note type personal computer, a TV monitor and the like and a display panel carrier therefor.
2. Description of Related Art
A conventional method and equipment for manufacturing a flat-panel display unit will be explained below based on FIGS. 11 through 14.
A display panel which constitutes a display area of the flat-panel display unit comprises a plurality of pixels, through which a level of transmission or reflection of light may be controlled in accordance to control made from the outside, between two insulating substrates. Electrode areas, color filters and others are formed on one side of each of the insulating substrates via a number of processes and then liquid crystal substance and others are sandwiched therebetween to form a cell structure, i.e. the display panel. Next, driving circuits and others are electrically connected to edge portions of the display panel further via a number of processes.
Thus, the display panel and the insulating substrates must be processed through the number of processes and by a number of processing machines in order to manufacture the flat-panel display unit.
At first, alignment of the display panel or the insulating substrate with a working section of the processing machine in the prior art technology will be explained below with reference to conceptual drawings in FIGS. 11 and 12. It is noted that the display panel will be assumed to be a liquid crystal cell in the explanation below.
FIG. 11 shows a step of rough alignment. A liquid crystal cell 101 is conveyed to a working stage 134 of the processing machine through a roller conveyor 102 or manually by an operator. At this time, the liquid crystal cell 101 is guided by guide rollers 132 and is pushed in until its outer edge abuts with guide pins 133. The rough alignment is conducted thus by the abutment. The alignment accuracy is as rough as about 0.3 mm or more. Even if the accuracy of the dimension of the guide pins and the abutment is improved, the dimensional accuracy of the glass substrates used in the liquid crystal cell 101 is dispersed. Further, the positional accuracy of the edge of the glass substrate with the electrode terminal is dispersed, so that it is difficult to align them with the higher accuracy. Further, there has been a problem that if the guide pin 133 is made of a relatively rigid material in order to maintain the dimensional accuracy, the edge of the glass substrate might be broken when it abuts with such a pin.
FIG. 12 shows a step of fine alignment. The fine alignment is implemented by means of an image processor provided with a CCD camera 106 and an NC (numeral control) table 103. The liquid crystal cell 101 having alignment marks 111 at corners thereof having nearly a rectangular shape is placed on the NC table. When the alignment mark 111 enters the field of view of the CCD camera 106, the image processor calculates a direction and distance of the misalignment and calculates motion of the NC table 103 necessary for the alignment. Thereby, the NC table 103 is driven by a motor driver 130 to align the liquid crystal cell 101. The use of two CCD cameras 106 allows finer alignment to be made and normally about 0.01 to 0.02 mm (10 to 20 .mu.m) may be obtained readily. Even in the roughest case, about 0.05 mm (50 .mu.m) of accuracy may be obtained readily. Such fine alignment is required in a TCP pre-bonding step described later for example.
In the prior art technology, there has been no simple method suited to the case when the required accuracy is 0.05 mm to 0.3 mm (e.g. an ACF heating step described later) and the use of the expensive image processor has required the excessive investment on the facility and disallowed easy change of the facility.
Next, a flow of prior art manufacturing steps of the flat-panel display unit will be explained below by exemplifying a series of steps for mounting TCPs (Tape Carrier Package, called also as TAB) on the liquid crystal cell. FIG. 13 is a flow chart thereof.
The TCP comprises a driving IC for supplying driving voltage and the like to the liquid crystal cell mounted on a flexible substrate.
The process for mounting the TCP on the liquid crystal cell comprises five steps of attaching an ACF (Anisotropic Conductive Film), heating the ACF, pre-bonding the TCP, post bonding the TCP and soldering a PCB (Printed Circuit Board) as shown in the figure and the above-mentioned rough alignment is carried out in each step. Because the liquid crystal cell is conveyed solely to the next machine between the steps by means of rubber rollers or manually, the aligning operation had to be carried out repeatedly.
There has been a problem as described later also in the aligning operation in the TCP pre-bonding step which requires the fine alignment within the five steps described above.
As shown in FIG. 14, the liquid crystal cell 101 is conveyed onto a cell mount 163 of a pre-bonding machine and the rough alignment is carried out at this time. The liquid crystal cell 101 is placed so as to protrude toward the front side from the cell mount 163 like a shelf. Two CCD cameras are set below the shelf portion and a light source 160 and two monitor displays 161 are provided behind the cell mount 163.
At first, it is determined by the monitor displays 161 whether terminals at both ends of an area where the TCP is to be mounted on the edge portion of the liquid crystal cell 101 enter the field of views of the two CCD cameras. When they do not enter the field of view, the rough alignment is repeated. Then, the terminals at the both ends are controlled so that they come around the center of the field of view of each CCD camera by a pitch feed plate 162 provided on the cell mount 163.
The TCP 113 is set at the edge of a TCP mounting arm 136 turnably attached on a NC table for TCP and is turned and conveyed to the edge of the liquid crystal cell 101. Next, the both ends of the TCP terminal section are positioned accurately with the terminals at both ends of the to-be-mounted area on the liquid crystal cell, where TCP is to be mounted, by the move of the NC table for TCP made through a command from the image processor. Then, after confirming by the monitor displays that the fine alignment has been implemented, a pressuring head is applied to a TCP press-bonding section.
Such alignment method has had a problem that the processing time is prolonged because the further alignment is implemented with respect to the respective liquid crystal cells 101 by the high functional machine having the accuracy in the level of 0.01 to 0.02 mm (10 to 20 .mu.m), after the alignment in the level of 0.3 mm in the rough alignment described above. Further, the field of view of the CCD cameras of the accurate alignment unit must be large.
Further, because the rough alignment of the display panel with the working section of a processing machine needs to be repeatedly implemented in each step in the prior art technology described above, the processing steps and processing time increase that much.
Still more, because such complicated and expensive machine like the image processor has been used even when no such fine alignment is required, the facility cost related to the alignment has been excessive. When the image processor stops due to some trouble, it takes time to recover it and during that time, the flow of the manufacturing steps had to be stopped.
Further, because the rough alignment is made by abutting the outer edge of the display panel with the guide pins, there has been a case when the edge thereof is broken especially when the display panel is made of glass, increasing the production cost because it cannot be used again if it is broken. Further, because the conveyance needs to be stopped to change the guide rollers or setting of the width thereof when the width of the substrate is changed, it has been an obstacle in improving the productivity.
Accordingly, it is an object of the present invention to solve the aforementioned problems by providing a method and apparatuses for manufacturing a flat-panel display unit which allow the productivity to be improved and the investment on the facility to be suppressed low.
Further, it is an object of the present invention to provide a method which allows the production to be continuously carried out even when specifications of the substrate such as a width thereof is changed.
It is also an object of the present invention to provide a display panel carrier which allows the display panel or electrode substrates thereof to be conveyed safely and simply and the predetermined positional relationship in connection with alignment to be reproduced by fitting or abutting with a processing machine.